Human blood platelets in platelet-rich plasma (PRP) aggregate when decompressed by 3 different methods: (1) reduced barometric pressure to 1/2 atmosphere at 38 degrees C for 2 hours; (2) hydrodynamic decompression, i.e. initially compress to 8,000 and then slowly decompress to 14.7 PSI in about 2 hours; and (3) hydrodynamic decompression by Bernoulli effect. Bernoulli effect decompression is produced by squeezing a 300 cc plastic bag containing PRP, which is driven through a constriction of 0.5 mm in 3 mm plastic tubing. Platelet aggregation is observed by a differential interference contrast optical microscope. Decompression platelet aggregation can be prevented by the drug piracetam and pentoxifylline at the concentration of 0.5 and 1.0 mM. They are potentially useful in the prevention of decompression platelet aggregation in acute mountain sickness, decompression or diver's disease, and in stroke and heart attack. A magnetic concentration of red blood cells (RBC) infected with malaria parasite is being developed. The underlying principle is that malaria parasite in RBC metabolizes the hemoglobin into the pigment zooheme. The pigment zooheme is paramagnetic, which means that infected RBC are attracted and attach to a strong magnet. In order to create the strong magnetic field, a very fine wire of 0.001 inch in diameter was drawn from a special stainless steel. A small pill box containing the fine wire mesh when placed between the horns of a powerful ALNICO magnet becomes a "filter" for infected RBC. In situ microscopic observation shows that malaria parasite-infected RBC are attached to 0.001 inch stainless steel wires while in the horns of ALNICO magnet having the field strength of 3 kilogauss. Because young parasites have not produced a large amount of the pigment zooheme, they are separated from the old ones.